YOU might be forgiven for not having heard of Infiniti. Although part of the Nissan family, it's very much a premium brand in its own right and while its cars share many parts from its Nissan cousins, Infiniti is trying to make its brand a lot stronger in the UK.

Aside from expanding its network of dealerships, the firm wants to thrust its broad range of models into the minds of buyers that might normally have ventured off to BMW or Audi forecourts.

And there's plenty on offer, should the hand holding the pen over your cheque book now be backing away from writing 'Audi' on the top line.

One of the highlights of Infiniti's current crop is the the G37 Coupe, which is a striking four-seater with the same 320bhp V6 engine you'd normally find in Nissan's 370Z sports car.

But this is more of a grand tourer, with a beautifully comfortable interior, a much softer ride, far more cabin space and several luxuries you'd not normally see in a driver-focused car.

That's not to say it's not sporty, though. Mated to the excellent engine is a fantastic seven-speed gearbox and there's a clever suspension set-up with four-wheel steering and a limited slip differential to keep the handling tight and responsive.

The engine uses a variable valve timing system which Infiniti says gives a smooth and predictable power delivery. In practice, this means the best of the engine's power and character is to be found above 4,000 revs - and there's a real monster up there if you do choose to wake it.

So what you're actually getting with the G Coupe is two cars in one. You can either leave the gearbox in fully automatic mode, set the adaptive cruise control up and let the car waft you along effortlessly, or you can knock the gearbox into sport mode and get properly involved.

And it's when the car makes its leap from luxury grand tourer to full-on hooligan you start to feel the benefit of the multi-link suspension and that four-wheel steering.

Tugging away at the magnesium paddle-shifters you also get the full aural delight of the fabulous 3.7 litre engine and, above around 4,000rpm, you get an assured surge of acceleration. It's not unusual to see the traction control light flash up at this point as the valve timing system wakes up the rest of the engine and delivers its full assault, leaving the wheels scrabbling for traction.

While you're really pushing the G37, you'll quickly become aware of how beautifully set up it is inside. Rear cabin space is a tad tight compared to some rivals, but the pay off is a huge and supportive pair of front seats wich can be electronically moulded into almost any shape you could imagine.

Cleverly, the instrument binnacle moves in conjunction with the adjustment of the chunky leather steering wheel, meaning the driving position is nigh-on perfect. It's impossible to feel uncomfortable in this car.

Unlike its rivals, Infiniti likes to ensure buyers know what they're getting when they pick a model from its its range. So instead of a long list of options, each variant has a set specification and there are hardly any boxes to tick.

This doesn't mean everything's free, of course, but the pricing structure is still fairly keen. The basic GT spec, with an auto box, comes in slightly cheaper than the BMW 335i SE Coupé before - and that's before any options are added to the latter car.

At the other end of the spectrum the top spec G37 S Premium stacks up quite well against the BMW 335i M Sport Coupé because there's still a few empty boxes on the BMW's options list that need fairly pricey ticks to keep up with the Infiniti.

It's not all good news. It might be priced keenly on the forecourt when compared to its rivals but residual values come resale time are likely to tell another tale. It's also fairly thirsty and there are less dealers around for servicing and maintenance.

But one thing the germans will never take away from this otherwise excellent Japanese newcomer is its exclusivity.

The G37 Coupe is venturing out into a market sector which has become known for producing some of the industry's best cars but it's doing a brilliant job of its first proper challenge.

So while you may not have heard of Inifiniti just yet, if the company can continue this fine form then expect their cars to become a much more familiar site over the coming months.